The invention relates to a vibrational linear conveyor for conveying workpieces and powdery or granular materials with a useful mass and a counter mass, which are equal in magnitude, are mounted separately at a vibrating system and, for conveying, can be brought into an opposite oscillating or vibrating movement over an electromagnetic exciter element comprising a magnet coil and a magnet armature, both of which are parts of the useful or counter mass. By means of the oscillating or vibrating movement, the workpieces or materials on a trough-like conveying element, which is part of the useful mass, are transported along the conveying element.
Such a vibrational linear conveyor is known, for example, from the European patent 0 529 185 B1. The conveying principle of such a linear conveyor is based on a micro-flow principle. Due to the oscillating or vibrating movement of the conveying element, the workpieces or materials on the latter are thrown in the conveying direction. Admittedly, the throwing movement is minimal. However, because of the high oscillating or vibrating frequency, there is a continuous longitudinal movement. By these means, workpieces, which are to be installed or passed on further, are transported or ordered in the form of subminiature components, which are passed on, for example, by a vibrational helical conveyor to the linear conveyor and, over the latter, are then passed onto an automatic production machine. It is also possible to convey powdery or granular materials or the like. In order to avoid, as far as possible, any transferor of vibrations to a table or a frame, at or on which such a linear conveyor is disposed, a useful mass and a counter mass are provided for a vibrational linear conveyor of the type named above and brought into the opposite oscillating or vibrating movement by an exciter element. In other words, they carry out an opposite, sinusoidal oscillating movement. For producing the micro-throw movement, this oscillating movement is directed upward at an angle in the conveying direction. An electromagnetic exciter element with a magnet coil and a magnet armature and an associated magnet armature are provided for producing the vibration, the magnet coil being disposed, for example, at the counter mass and the magnet armature at the useful mass or vice versa. When the exciter element is operated appropriately, a continuous, opposite movement is produced because of the magnetic fields generated between the magnet coil and the magnet armature and the movement, in turn, is transferred to the respectively assigned masses.
The EP 0 529 185 B1 discloses a linear conveyor of the type named above, for which the useful mass and the counter mass are disposed lying next to one another, that is, lying parallel to one another. They are disposed at two spring elements, which form part of the vibrating system and are disposed at an angle with respect to the vertical. However, it is a disadvantage of such a linear conveyor that, because of the parallel arrangement of the masses, the vibrating forces, resulting from the vibrational accelerations of the two masses, although they act in mutually opposite directions, do not act on the same line of action. Consequently, in spite of the given equality of the useful and counter masses and, in the final analysis, of the reaction magnitude at the foundation, where the linear conveyor is mounted at the floor, these forces admittedly cancel one another. However, because of the asymmetrical arrangement and the divergence of the force directions, vibrating torques are produced, which are responsible for a tilting vibration of the linear conveyor as well as for a rotating vibration with respect to the vertical, which can lead to lateral vibrations especially at the ends of the conveying element. As a result, there may be difficulties with the conveying and transferring of workpieces or materials.
A further disadvantage of such a linear conveyor lies therein that its operational equipment is relatively complicated. In order to make a conveying operation possible utilizing the resonance behavior, it is necessary, on the one hand, to match the useful and counter masses as accurately as possible in their vibrational mounting, so that the natural frequency, with which each mass vibrates, is matched to the exciter frequency of the exciter element. This is accomplished with appropriate adjustment of the mounting of the respective mass at the vibrating system or at the springs, which is very complicated and requires much experience. Whenever there is a change in the mass relationship, matching must be carried out once again. In actual practice, however, it is frequently the case that a more flexible method of working is aimed for, that is, that a rapid exchange, for example, of workpieces, which are to be installed by a production machine, which necessarily also leads to the need to supply the other workpieces, which are to be installed, by means of a linear conveyor. The conveying element would have to be exchanged frequently for this purpose. However, this is not at all possible without the very expensive new installation.